Neutralizing anti-interleukin-1β antibodies modulate fetal blood-brain barrier function after ischemia.

Abstract We have previously shown that increases in blood–brain barrier permeability represent an important component of ischemia–reperfusion related brain injury in the fetus. Pro-inflammatory cytokines could contribute to these abnormalities in blood–brain barrier function. We have generated pharmacological quantities of mouse anti-ovine interleukin-1β monoclonal antibody and shown that this antibody has very high sensitivity and specificity for interleukin-1β protein. This antibody also neutralizes the effects of interleukin-1β protein in vitro. In the current study, we hypothesized that the neutralizing anti-interleukin-1β monoclonal antibody attenuates ischemia–reperfusion related fetal blood–brain barrier dysfunction. Instrumented ovine fetuses at 127 days of gestation were studied after 30 min of carotid occlusion and 24 h of reperfusion. Groups were sham operated placebo-control- (n = 5), ischemia-placebo- (n = 6), ischemia-anti-IL-1β antibody- (n = 7), and sham-control antibody- (n = 2) treated animals. Systemic infusions of placebo (0.154 M NaCl) or anti-interleukin-1β monoclonal antibody (5.1 ± 0.6 mg/kg) were given intravenously to the same sham or ischemic group of fetuses at 15 min and 4 h after ischemia. Concentrations of interleukin-1β protein and anti-interleukin-1β monoclonal antibody were measured by ELISA in fetal plasma, cerebrospinal fluid, and parietal cerebral cortex. Blood–brain barrier permeability was quantified using the blood-to-brain transfer constant ( K i ) with α-aminoisobutyric acid in multiple brain regions. Interleukin-1β protein was also measured in parietal cerebral cortices and tight junction proteins in multiple brain regions by Western immunoblot. Cerebral cortical interleukin-1β protein increased ( P P P P P K i across the brain regions ( P K i showed an inverse linear correlation (r = − 0.65, P